2D BA₂PbI₄ Regulating PbI₂ Crystallization to Induce Perovskite Growth for Efficient Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Chemistry

Background:

• Controlling perovskite film crystallization is key for high-efficiency perovskite solar cells (PSCs).
• n-butylammonium (BA) cations enhance PSC stability due to their long alkyl chains.
• The use of BA-based 2D perovskites as crystallization seeds is underexplored.

Purpose of the Study:

• To investigate the use of BA₂PbI₄ as a seed layer for regulating PbI₂ crystallization.
• To enhance the crystallinity, orientation, and grain size of perovskite films.
• To improve the power conversion efficiency (PCE) and stability of PSCs.

Main Methods:

• Employing BA₂PbI₄ as nucleation centers to control PbI₂ film crystallization.
• Fabricating perovskite films with preferential (001) crystal orientation and large grain sizes (>2 µm).
• Characterizing the resulting perovskite films and evaluating the performance and stability of the fabricated PSCs.

Main Results:

• Achieved a porous PbI₂ film with high crystallinity using BA₂PbI₄ seeds.
• Realized perovskite films with preferential (001) orientation and grain sizes exceeding 2 µm.
• PSC devices demonstrated a high PCE of 24.30% and retained 91.70% of initial PCE after 300 hours of thermal aging at 85°C.

Conclusions:

• BA₂PbI₄ is an effective seed material for controlling perovskite crystallization.
• This seeding strategy significantly enhances PSC performance and operational stability.
• The findings open new avenues for developing stable and efficient perovskite solar cells.